An unsaturated hydrocarbon X absorbs two hydrogen molecules on catalytic hydrogenation and also gives following reaction : B(3 - oxo - hexanedicarboxylic acid) X will be :-

The radius of the second Bohr orbit, in terms of the Bohr radius, a₀, in Li²⁺ is :

A metal (A) on heating in nitrogen gas gives compound B. B on treatment with H₂O gives a colourless gas which when passed through CuSO₄ solution gives a dark blue-violet coloured solution. A and B respectively, are :

Consider the following plots of rate constant versus $${1 \over T}$$ for four different reactions. Which of the following orders is correct for the activation energies of these reactions?